Correlation of membrane potentials (intracellular microelectrodes) of adenocortical cells with steroidogenic activity. Effects of stimulants of steroidogenesis on electrophysiological properties. Characterization of steroidogenesis by adrenocortical tissue in a flowing system in which steroid output is monitored continuously by fluorimetry. Comparison of the steroidogenic responses to ACTH, cyclic nucleotides, inhibitors, ions, etc. Utilization of the system as an automated assay for ACTH. Coupling of the assay for ACTH with the release of ACTH by pituitary tissue in vitro to assay CRF (corticotropin releasing factor) activity. The use of the CRF assay to study the properties of hypothalamic CRF.